如何使用 ViewPager2 在 TabLayout 中实现列表项

Question

我是 Android 开发新手，目前正在使用 Viewpager2 学习 TabLayout。 我已经在我的适配器中硬编码了片段。顺便说一句，我需要将我所有的片段添加到列表中。那么如何在列表或 Arrylist 中添加片段。请帮助我。

这是适配器代码：

public class ScreenSliderAdapter extends FragmentStateAdapter{

public ScreenSliderAdapter(@NonNull FragmentManager fragmentManager, @NonNull Lifecycle lifecycle) {
    super(fragmentManager, lifecycle);
}

@NonNull
@Override
public Fragment createFragment(int position) {

    if (position==0) {

        return new BangladeshFragment();

    } else if (position==1) {

        return new BrazilFragment();

    } else if (position==2) {

        return new MaltaFragment();

    }

    return new BangladeshFragment();
}

@Override
public int getItemCount() {

    return 3;
}

}

这是主要活动代码：

公共类 MainActivity 扩展 AppCompatActivity {

FragmentManager fm;
ScreenSliderAdapter sa;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


    fm = getSupportFragmentManager();
    sa = new ScreenSliderAdapter(fm,getLifecycle());

    ViewPager2 pager = findViewById(R.id.pager);

    TabLayout tabLayout = findViewById(R.id.tabLayoutID);
    tabLayout.addTab(tabLayout.newTab().setText("Bangladesh"));
    tabLayout.addTab(tabLayout.newTab().setText("Brazil"));
    tabLayout.addTab(tabLayout.newTab().setText("Malta"));

    pager.setAdapter(sa);


    tabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
        @Override
        public void onTabSelected(TabLayout.Tab tab) {

            pager.setCurrentItem(tab.getPosition());
        }

        @Override
        public void onTabUnselected(TabLayout.Tab tab) {

        }

        @Override
        public void onTabReselected(TabLayout.Tab tab) {

        }
    });


    pager.registerOnPageChangeCallback(new ViewPager2.OnPageChangeCallback() {
        @Override
        public void onPageSelected(int position) {

            tabLayout.selectTab(tabLayout.getTabAt(position));
        }
    });
}

}

Answer 1

活动

import android.os.Bundle;
import androidx.appcompat.app.AppCompatActivity;
import androidx.viewpager2.widget.ViewPager2;

import java.util.ArrayList;

public class MyActivity extends AppCompatActivity {

    ViewPager2 myViewPager2;
    MyAdapter MyAdapter;
    private ArrayList<String> arrayList = new ArrayList<>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_my);

        myViewPager2 = findViewById(R.id.view_pager);

        arrayList.add("Item 1");
        arrayList.add("Item 2");
        arrayList.add("Item 3");
        arrayList.add("Item 4");
        arrayList.add("Item 5");

        MyAdapter = new MyAdapter(this, arrayList);


        myViewPager2.setOrientation(ViewPager2.ORIENTATION_VERTICAL);

        myViewPager2.setAdapter(MyAdapter);
    }
}

新功能

myViewPager2.registerOnPageChangeCallback(new ViewPager2.OnPageChangeCallback() {
        @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
            super.onPageScrolled(position, positionOffset, positionOffsetPixels);
        }

        @Override
        public void onPageSelected(int position) {
            super.onPageSelected(position);

            Log.e("Selected_Page", String.valueOf(position));
        }

        @Override
        public void onPageScrollStateChanged(int state) {
            super.onPageScrollStateChanged(state);
        }
    });

我的适配器

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import java.util.ArrayList;

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> {

    private Context context;
    private ArrayList<String> arrayList = new ArrayList<>();

    public MyAdapter(Context context, ArrayList<String> arrayList) {
        this.context = context;
        this.arrayList = arrayList;
    }

    @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(context).inflate(R.layout.list_item, parent, false);
        return new MyViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull MyViewHolder holder, int position) {
        holder.tvName.setText(arrayList.get(position));
    }

    @Override
    public int getItemCount() {
        return arrayList.size();
    }

    public class MyViewHolder extends RecyclerView.ViewHolder {
        TextView tvName;

        public MyViewHolder(@NonNull View itemView) {
            super(itemView);
            tvName = itemView.findViewById(R.id.tvName);
        }
    }
}